Aids regulation of normal body temperature, as the evaporation of sweat from the skin removes excess heat from the body.

Maintains blood volume

Water needs vary depending on diet, activity, environmental temperature and humidity. General water requirement is difficult to establish. The recommendation are sometimes expressed in proportions to the amount of energy expended under average environmental conditions. The recommended water intake for a person who expend 8000kj a day is for example 2-3 litre per day. This recommendation is in line with the Adequate Intake for total water set by the DRI committee.

The obvious dietary source of water is water itself and other beverages, but nearly all food contain water. Most fruit and vegetables contains more than 60% water and up to 99%, while some meats and cheese contain up to 50% water. See table 5.1 for foods and their water percentages.

The body must excrete 500ml (2 cups) of water a day, as urine, to carry away all the waste produced by metabolic activities. In addition to urine, water is lost from the lungs as vapor and from the skin as sweat. The amount of fluid lost from each sources varies, depending on the environment (such as heat and humidity) and physical conditions (such as exercise or fever). On average daily water losses is about 2.5 litre

Water intake should be significantly higher than water losses to prevent dehydration. Table 5.2 indicates signs and symptoms of dehydration.

One of the most common causes of dehydration is water loss during exercise without replacing the water loss. In many cases fluid and mineral loss in sweat can be replaced by drinking plain cool water or eating regular food. Other cases however demand rapid replacement of fluid and electrolyte. Endurance athletes can easily lose 1.5L or more fluid during each hour of activity. To prepare for fluid losses an athlete must hydrate before exercise and even in the days before an event to ensure maximum hydration at the start of an event. To replace fluid loss the athlete must rehydrate during and after exercise. Table 5.3 explains the hydration schedule for endurance athletes

WHEN TO DRINK

AMOUNT OF FLUID

2 – 3 hours before activity

2 – 3 cups

15 min before activity

1 – 2 cups

Every 15 min during activity

½ – 1 cups

After activity

4 cups for each kg lost after exercise

Table 5.3

During exercise when sweating occurs, small amounts of electrolytes (electrically charged minerals sodium, potassium, chloride and magnesium) are lost with water. Losses are greater in beginners; training improves electrolyte retention. To replenish electrolyte loss athletes ordinarily need only to eat a balanced diet that meets energy and nutrient need. In eventscompares popular sports drinks. more than an hour or in very hot, humid conditions, sports drinks may be needed to replace fluids and electrolytes.

Hydration is critical to optimal performance. As stated previously water best meets the fluid needs of most people, yet manufacturers market many good-tasting sports drinks that delivers both fluid, electrolytes and carbohydrates. The term sports drink generally refers to beverages that contains carbohydrates and electrolytes in a specific concentration.

Lets take a closer look at the most popuelectrolyte solution with less sugar and carbohydrates possibly after a hot, humid higer intensityrink on the market:

Energade (100ml): 130kj; 8g carbohydrates; 6g sugar

Energade lite (100ml): 60kj; 3.2g carbohydrates; 2g sugar

Powerade (100ml): 129.5kj; 7.3g carbohydrates; 5.5g sugar

Lucozade (100ml): 265kj; 15g carbohydrates; 13g sugar

Lucozade zero (100ml): 9kj; 0, 1g carbohydrates; 0, 1g sugar

BOS Sport (100ml): 114kj; 6.4g carbohydrates; 6.4g sugar

Game (100ml): 122kj; 7.2g carbohydrates; 6g sugar

Vitamin water (100ml): 85kj; 5.2g carbohydrates; 5.2g sugar

Oshee (100ml): 5kj; 0g carbohydrates; 0g sugar

If you are looking for a hydration and electrolyte solution with less carbohydrates and sugars, possibly after a hot and humid workout, that was less streneous, you would rather look out for lite options like Energade lite, Lucozade zero, and Oshee. These products also has a stabilizing effect on bloodsugar levels. However after finishing a streneous prolonged workout session of 2-3 hours or more, in humid, hot weather, you might need a sports drink with higer carbohydrate content.